What with Easter falling in March this year there's only one kind of egg I have in mind for this month's Poster poems; I'm talking about chocolate eggs, of course. There are many aspects of the European conquest of the Americas that are to be deeply regretted, but few of us are so pure in our scruples as to be able to lament the introduction of chocolate into the Old World.

When it arrived in Spain in the 16th century, chocolate was very much a luxury and its consumption was to remain the preserve of the wealthy for 200 years or so. It is hardly surprising, then, that in its early appearances in English poetry it serves as a symbol for everything opulent. In the second Canto of Pope's "Rape of the Lock" it is associated with the luxury of Belinda's morning toilet where its scent serves as an ironic mock-heroic equivalent to the fumes of hell that accompany the punishment of Ixion.

In "To Mr F Now Earl of W", Pope's friend and fellow-poet Anne Finch uses the dark nectar as shorthand for the Augustinian beau monde, a world of indolence and disdain for such a theme for poetry as a woman's devotion to a mere spouse.

By the time Thomas Hood was writing, chocolate was a more affordable everyday commodity, thanks in the main to the efforts of a number of Quaker families: Rowntree, Cadbury, and Fry among them. Hood's "A Friendly Address To Mrs Fry In Newgate" concerned a member of one of these families, Elizabeth Fry, née Gurney, a social reformer who set up a school in the old women's prison and campaigned against capital punishment. Clearly Hood did not approve of Mrs Fry's reforming zeal, but he couldn't help a passing word in praise of the family chocolate.

Perhaps because of its relative novelty, chocolate plays a peripheral role in these poems. By the early 20th century, chocolate had become an everyday treat for most residents of the western world. This newfound ubiquity can also be seen in the more prominent role the sweet stuff plays in poems where it is mentioned. "Harlem Sweeties" by Langston Hughes is a confectionery litany in praise of Harlem girls in all their glory. Chocolate is moving centre stage.

Michael Rosen's "Chocolate Cake" introduces another note, that sense of guilt that often accompanies a major overindulgence, especially a furtive one. How many of us can honestly say that we never sneaked down to the kitchen in the middle of the night to indulge our taste for sugary, milky cacao only to wake up regretting it next morning? Or is that just me?

But of all the poets I've come across in my chocolate poetry egg-hunt, the one who was most straightforwardly celebratory is Dorothy Porter. Her poem called, simply, "Chocolate" is another love poem in which chocolate and the beloved become as one. In "Lawns", the speaker, who is "off the wagon" on a four-bars-a-day habit, declares "chocolate/is my valium", a shield against the stresses of a world bemired in incomprehensible order.

And so this month the theme of the challenge is chocolate in its multifarious splendour. Solid, liquid, hot or cold, by itself or as an ingredient in your favourite dessert, for its own sake or as a symbol for something else: chocolate poems are for sharing. And if you're one of those rare souls I've heard of who don't like chocolate, you could write a poem explaining your extraordinary reasoning. Now, there's a challenge.